CA2265439A1

CA2265439A1 - Additive concentrate for fuel compositions

Info

Publication number: CA2265439A1
Application number: CA002265439A
Authority: CA
Inventors: Gail Mclean
Original assignee: Individual
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1996-09-12
Filing date: 1997-09-11
Publication date: 1998-03-19
Also published as: EP0938533A1; JP2001500183A; ATE209244T1; US6277158B1; EP0938533B1; DE69709780D1; NO991172D0; NO991172L; MY132728A; WO1998011175A1; EP0829527A1; DE69709780T2

Abstract

An additive concentrate for use in fuels, especially in gasoline for internal combustion engines, comprising (a) 0.2 to 10 wt.% ashless friction modifier which is liquid at room temperature and pressure selected from (i) n-butylamine oleate or derivatives thereof, (ii) a substance comprising tall oil fatty acid or derivatives thereof, and (iii) mixtures of (i) and (ii); (b) 10 to 80 wt.% deposit inhibitor, and (c) carrier fluid. The particular selection of friction modifier (a) enables a stable additive concentrate to be formulated without the need for additional solubilising agent for the friction modifier, whilst containing sufficient friction modifier to achieve a significant benefit in friction loss, when incorporated in gasoline used to fuel an internal combustion engine, and hence an improvement in fuel economy.

Description

?CA 02265439 1999-03-09W0 98/11175 PCT/EP97/05015Additive concentrate for fuel compositionsThis invention relates to an additive concentrate for use in fuels, especially ingasolines for internal combustion engines.It is well-known that the performance of gasolines and other fuels can beimproved through the use of additive technology. For example, detergents can be addedto inhibit the formation of intake system deposits, thereby improving engine cleanliness.More recently it has been suggested that friction modi?ers may be added to gasolines toincrease fuel economy by reducing engine friction. In selecting suitable components for adetergent/friction modi?er additive package it is important to ensure a balance ofproperties. The friction modi?er should not adversely affect the deposit control of thedetergent. In addition the package should not exhibit any harmful effects on theperformance of the engine, such as valve sticking.Current practice in the supply of gasoline i.s generally to pre-mix the fueladditives into a concentrate in a hydrocarbon solvent base, and then to inject theconcentrate into gasoline pipelines used to ?ll tankers prior to delivery to the customer.Under present operating conditions, the maximum amount of concentrate that can beincorporated into a tanker of gasoline is typically about 2000 ppm based on the weight ofthe gasoline, of which about 700-1500 ppm is taken. up by a conventional detergent-containing gasoline additive package. To facilitate injection of the concentrate into thegasoline, it is important that the concentrate is in the form of a low viscosity,homogeneous liquid. Problems have been encountered in achieving a stable concentratedue to the poor solubility of conventional friction modi?ers, especially at lowtemperatures. The solubility of the friction modi?er may be assisted by employingsolubilising agents. However, the amount of solubilising agent required to solubilise thedesired level of friction modi?er in the concentrate often exceeds the maximum amountpossible given the constraints on the amount of concentrate that can be injected into thegasoline, and the amount of solubilising agent that can be contained in the concentrate.In addition, some solubilising agents tend to react adversely with the friction modi?er,or other additives contained in the concentrate, causing chemical degradation and/or areduction in performance in the resulting gasoline composition.?CA 02265439 1999-03-09W0 98/11175 PCT/EP97/05015Accordingly, there is a need for a detergent/friction modi?er additive concentratefor gasoline that provides both deposit control and friction reduction, which is stable overthe temperature range at which the concentrate may feasibly be stored, and which doesnot adversely affect the performance and properties of the ?nished gasoline or engine inwhich the gasoline is used.The present invention provides an additive concentrate comprising by weightbased on the total weight of the concentrate:(a) 0.2 to 10 % ashless friction modi?er which is a liquid at room temperature andpressure selected from (i) n-butylamine oleate or derivatives thereof, (ii) a substancecomprising tall oil fatty acid or derivatives thereof, and (iii) a mixture of (i) and (ii),(b) 10 to 80 % deposit inhibitor, and(c) 10 to 80 % carrier ?uid.The particular selection of friction modi?er (a) enables a stable additiveconcentrate to be formulated Within the current constraints of a maximum ofapproximately 2000 ppm by weight concentrate in the ?nished gasoline, of which up toabout 1500 ppm is deposit inhibitor, whilst containing suf?cient friction modi?er toachieve a signi?cant bene?t in friction loss and hence an improvement in fuel economy,and without the need for additional solubilising agent for the friction modi?er.Solubilising agents, for example hydrocarbon solvents such as alcohols, may be included ifdesired, and therefore are not excluded from the scope of the present invention, but theyare not an essential requirement.The friction modi?er is preferably a liquid over the temperature range at whichthe additive concentrate is likely to be stored. Typically this temperature range is from-20 to +35Â°C.?CA 02265439 1999-03-09wo 98/11175 PCTIEP9 '7/05015The friction modi?er may be n-butylamine oleate or a derivative thereof, asubstance comprisingÂ» tall oil fatty acids or derivatives thereof, or a mixture of these.Despite substantial research investigating a wide range of available friction modi?ercompounds, it has been found that only these two compound types provide the bene?tsexplained above.n-Butylamine oleate has the formula:, O//CH3 - (CH2)7 - CH:CH - (CHI2)7 - C\6' +NH3 C4H1oAn example of a suitable commercially available n-Ebutylamine oleate friction modi?er isRS 124 supplied by Bitrez Ltd.The substance comprising tall oil fatty acids may either be 100% tall oil fattyacids, or substantially 100% tall oil fatty acids, or may be a mixture of tall oil fatty acidsand other fatty acids or derivatives thereof. Preferably such a mixture contains at least50 wt%, more preferably at least 70 wt%, tall oil fatty acids. An example of a suitablecommercially available substance containing tall oil fatty acids is Tolad 9103 supplied byPetrolite Ltd.The amount of friction modi?er contained in the additive concentrate is from 0.2to 10 wt%, preferably from 0.5 to 5 wt%, and more preferably from 1 to 4 wt%, Onthe basis of a total concentrate treat level in the ?nished gasoline of 2000 ppm by weight,this corresponds to a treat level of friction modi?er in the ?nished gasoline of from 4 to200 ppm, preferably 10 to 100 ppm, more preferably 20 to 60 ppm.?CA 02265439 1999-03-09W0 93/ 11175 PCT/EP97I05015The deposit inhibitor (b) may be any suitable commercially available additive.Deposit inhibitors for gasoline, usually referred to as detergents or dispersants, are wellknown and a variety of compounds can be used. Examples include polyalkylene amines,and polyalkylene succinimides where the polyalkylene group typically has a numberaverage molecular weight of from 600 to 2000, preferably from 800 to 1400, and polyetheramines. A preferred detergent for the additive concentrate of the present invention is apolyalkylene amine, for example polyisobutylene amine. Examples of suitable PIB-amines are given in US Patent 4832702, the disclosure of which is incorporated herein byreference. Also, PIB-amine detergents can be obtained from, for example from ExxonChemical Company, Oronite and BASF.The amount of deposit inhibitor contained in the additive concentrate is from 10to 80 wt%, preferably from 20 to 75 wt%, and more preferably from 30 to 60 wt%. Basedon a total treat level of the additive concentrate of 2000 ppm by weight, this correspondsto a treat level of deposit inhibitor in the ?nished gasoline of from 50 to 1500 ppm,preferably 100 to 1000 ppm, more preferably 200 to 800 ppm.The carrier ?uid may be any suitable carrier ?uid that is compatible with thegasoline and is capable of dissolving or dispersing the components of the additive package.Typically it is a hydrocarbon ?uid, for example a petroleum or synthetic lubricating oilbasestock including mineral oil, synthetic oils such as polyesters or polyethers or otherpolyols, or hydrocracked or hydroisomerised basestocks. Alternatively the carrier fluidmay be a distillate boiling in the gasoline range. The amount of carrier ?uid contained inthe additive concentrate of the invention is from _10 to 80 wt%, preferably from 20 to 75wt%,and more preferably from 30 to 60 wt%.The additive concentrate according to the invention may also contain ademulsifier to inhibit the formation of emulsion in the gasoline which can form if thegasoline becomes contaminated with water. A demulsi?er is particularly advantageous ifthe friction modi?er is the substance comprising tall oil fatty acids as the acids tend topromote any emulsi?cation. Demulsi?ers for gasoline are well known and examples of?CA 02265439 1999-03-09W0 93/11175 PCT/EP97/05015suitable compounds are alkoxylated phenol formaldehyde resins. If a demulsi?er isemployed in the additive concentrate it is preferably in an amount from 1 to 4 ppm byweight based on the weight of the gasoline.The additive concentrate is preferably incorporated into the gasoline or other fuelby injection, although other suitable methods of incorporation may be used. To facilitateinjection the kinematic viscosity of the additive concentrate is preferably less than300 mm/s at -10Â°C, more preferably from 5 to 250 mm/s at -10Â°C, and most preferablyfrom 10 to 200 mm/s at -10Â°C. To achieve this viscosity a solvent is usually added to theconcentrate such as an aromatic hydrocarbon solvent or an alcohol. Examples includetoluene, xylene, tetrohydrofuran, isopropanol, isobutylcarbinol, n-butanol, andpetroleum hydrocarbon solvents such as solvent naphtha heavy, and Solvesso 150available from Exxon Chemical Company, and the like. Generally the amount of solventemployed is up to about 50 wt% based on the total weight of the additive concentrate, forexample from 10 to 20 wt%.The additive concentrate may also contain one or more other componentstypically contained in a fuel additive concentrate. These include, for example,antioxidants, corrosion inhibitors, conductivity enhancers, and the like. Generally each ofthese additional components is included in the concentrate in an amount whichcorresponds to a treat level of between 1 and 20 ppm by weight in the ?nished fuelcomposition.In another aspect the present invention provides a fuel composition comprisingcombustible fuel and from 500 to 2500 ppm by weight of an additive combinationcomprising components (a), (b) and (c) as de?ned in any of the preceding claims.The fuel used in the fuel composition of this invention is generally a petroleumhydrocarbon useful as a fuel e.g. gasoline, for internal combustion engines. Such fuelstypically comprise mixtures of hydrocarbons of various types, including straight andbranched chain paraf?ns, ole?ns, aromatics and naphthenic hydrocarbons. These?CA 02265439 1999-03-09W0 98/ 11175 PCT/EP97/05015compositions are provided in a number of grades, such as unleaded and leaded gasoline,and are typically derived from petroleum crude oil by conventional re?ning and blendingprocesses such as straight run distillation, thermal cracking, hydrocracking, catalyticcracking and various reforming processes. Gasoline may be de?ned as a mixture of liquidhydrocarbons or hydrocarbon-oxygenates having an initial boiling point in the range ofabout 20 to 60Â°C and a ?nal boiling point in the range of about 150 to 230Â°C, as 9determined by the ASTM D86 distillation method. The gasoline may contain smallamounts, eg up to 20 wt% and typically about 10 wt%, other combustibles such as alcohol,for example methanol or ethanol.Other fuels which may be used include combustible fuels such as kerosene, dieselfuels, home heating fuels, jet fuels etc.The invention shall now be illustrated with reference to the following Examples:Example 1A number of different additive concentrates were prepared by blending (a) afriction modi?er, (b) a detergent, and (c) a carrier ?uid. The friction modi?er was selectedfrom one of a number of commercially available products. The detergent was either apolyisobutylene-amine, a polyisobutylene succinimide or a polyether amine. Thesedetergents are well known and commercially available. For each detergent-type, the sameproduct was used throughout the Examples to ensure direct comparability of the results.The carrier ?uid, a polyether, was the same throughout the Examples.The stability of each of the resulting additive concentrates was determined byexposing samples of the concentrate to temperatures of -20Â°C, -10Â°C, Â°0C, ambient and+35Â°C and periodically inspecting the samples for sediment formation, water content,haze, and emulsion formation. A concentrate which remained stable for at least 3 monthsover the entire temperature range is considered to meet the stability requirements.?CA02265439 1999-03-09â'0 93/11175 PCT/EP97/05015- 7 -TABLE 1Examgle Friction Treat Detergent Â§h;b_i1i_11?g Modifier Level -20Â°C -10Â°C 0Â°C Ambient +35Â°C(ppm)1.01 Atsurf 594 100 PIBA <1 day <1 day <1 day <1 day <1 day1.02 Tolad 9103 25 PIBA >4 mths >4 mths >4 mths >4 mths >4 mths1.03 Tolad 9103 50 PIBA >4 mths >4 mths >4 mths >4 mths >4 mths1.04 Tolad 9103 100 PIBA >4 mths >4 mths >4 mths >4 mths >4 mths1.05 Tolad 9103 25 PEA >8 mths >8 mths >8 mths >8 mths A -1.06 Tolad 9103 50 PEA >8 mths >8 mths >8 mths >8 mths -1.07 Tolad 9103 100 PEA >8 mths >8 mths >8 mths >8 mths1.08 Tolad 9103 25 PIBS >1 mth >1 mth >1 mth >1 mth >1 mth(1240 ppm)1.09 ECA 5778/116 50 PIBA <1 week - - ~ -1.10 ECA 5778/116 50 PEA <1 week - - -1.11 EX69-169 50 PIBA >3 mths >3 mths >3 mths >3 mths -1.12 EX69-169 100 PIBA >3 mths >3 mths >3 mths >3 mths -1.13 EX69-169 50 PEA >4 mths >4 mths >4 mths >4 mths .1.14 EX69-169 100 PEA >4 mths >4 mths >4 mths >4 mths -1.15 M10229 50 PIBA <1 day - - - -1.16 M10229 50 PEA <1 day - - -1.17 SMO 50 PIBA <1 day >7 mths >7 mths >7 mths -1.18 SMO 100 PEA <2 days: >3 mths >3 mths >3 mths?CA 02265439 1999-03-09â'0 93/11175 PCT/EP97/05015- 3 .TABLE 1 (cont'd)Example Friction Treat Detergent StabilityNJ; Modi?er Level -20Â°C -10Â°C 0Â°C Ambient +35Â°C(ppm)1.19 n-BAO 25 PIBA >4 mths >4 mths >4 mths >4 mthe >4 mths1.20 n-BAO 50 PIBA >4 mths >4 mths >4 mths >4 mths >4 mths1.21 n-BAO 100 PIBA >4 mths >4 mths >4 mths >4 mths >4 mths1.22 n-BAO 25 PEA - - - -1.23 n-BAO 50 PEA >6 mths >6 mths >3 mths >3 mths -1.24 n-BAO 100 PEA >6 mths >6 mths >3 mths >3 mths -1.25 10G40 50 PIBA >3 mths <60 days - >3 mths -1.26 PMO 50 PIBA >5 mths - - - .1.27 PMO 100 PIBA >5 mths - - - -1.28 PMO 50 PEA >5 mths - - - -1.29 / PMO 100 PEA >5 mths - - - -1.30 Edenor PDO 50 PIBA >5 mths - - -1.31 Edenor PDO 100 PIBA >5 mths â - -1.32 Edenor PDO 50 PEA >5 mths - - - . â1.33 Edenor PDO 100 PEA >5 mths - - - -Notes to TABLE 1Atsurf 594 is a glycerol mono oleate friction modi?er available from ICI.Tolad 9103 is a tall oil fatty acid mixture friction modi?er containing about 75 wt.% activeingredient (remainder diluent) available from Petrolite.?CA 02265439 1999-03-09â'0 93â 11175 PCT/EP97/050l5ECA 57 78/ 1 16 is an oleic acid polyol ester friction modi?er available from Exxon ChemicalCompany.EX69-169 is Mayco EX69-169, a sulphurised fatty acid amide friction modi?er available fromMayco.M10229 is Additin M10229, a fatty amide friction modifier available from Rhein Chemie.SMO is Sorbitan mono oleate friction modi?er available from Henkel.n-BAO is n-butylamine oleate friction modi?er available from Bitrez.10G40 is a polyglycerol ester friction modi?er available from Caprol.PMO is pentaerithrytol mono oleate friction modi?er available from Henkel.Edenor PDO is pentaerithrytol di oleate friction modifier available from Henkel.PIBA is a polyisobutylene-amine detergent.PEA is a polyetheramine detergent.PIBS is a polyisobutylene succinimide detergent.The results show that only additive concentrates containing certain frictionmodi?ers are stable with each type of detergent over the full temperature range and treatlevels. These are: Tolad 9103, Mayco EX69-169,-n-BAO, Henkel PMO, and Edenor PDO.?CA 02265439 1999-03-09wo 98/11175 PCT/EP97/05015-10-Example 2The additive concentrates of Example 1 which passed the stability test werethen tested to ensure that the friction modi?er contained in the concentrate did nothave a detrimental affect on deposit control, inlet valve sticking, and friction and wear.Deposit control was measured according to standard engine test M102E (CECF-05-A-93). The lower the amount of deposits on the valve (measured in mg/valve) atthe end of the test, the better the deposit control of the additive package. A target levelis no more than 25 mg/valve.Valve sticking was determined by operating an Opel Ascona 1.61 4-cylinderengine with automatic choke for 100 hours under cyclic conditions. The cycle isintended to simulate urban driving with repeated cold starting of the engine. At theend of the test period the cylinder head is turned to allow the valves to fall freely out ofthe valve guides under their own weight. A clear pass is awarded when all of the valvesmove freely.Friction and wear were determined by a standard high frequency reciprocatingrig (HFRR) test. The test measures friction coefficient and wear scar diameter (WSD).The lower the values the better the performance of the additive package, the targetsbeing a friction coefficient of no more than 0.25 and a WSD of less than 500 u.The results are given in Table 2.?CA 02265439 1999-03-09â'0 93â 11175 PCT/EP97/05015-11-TABLE 2Example No. Deposit control Valve stick Friction coefficient WSD(mg/valve) (p.)1.02 9.61 â - -1.03 - Pass 0.25 4301.04 - - 0.178 3781.05 16 - I - -1.06 38 - 0.19 4701.07 - - 0.17 4251.08 12.75 Pass - -1.11 - - 0.228 5501.12 - - 0.206 5401.13 - - 0.277 6751.14 - - 0.228 5551.22 4.75 Pass 0.168 4251.23 ' - 0.151 4701.24 11.5 - - -1.25 5.5 Pass 0.179 4501.26 - - 0.169 4501.28 - - 0.269 6401.29 - - 0.239 5651.30 - - 0.262 6601.31 - - 0.195 515?CA 02265439 1999-03-09wo 98/11175 PCT/EP97/05015.12-TABLE 2 (cont'd)Example No. Deposit control Valve stick Friction coefficient WSD(mg/valve) (u)1.32 - - 0.269 6601.33 - - 0.252 6101.34 - - 0.27 6601.35 - - 0.22 560The results show that the best performance and least harm is achieved usingeither the Tolad 9103 or n-BAO friction modi?ers. All the other frictionmodi?ers either did not have a sufficiently low friction coef?cient (target no higher than0.25), and/or resulted in excessive wear (target WSD less than 500 u).Regarding preferred treat levels for the friction modi?ers, the n-BAO frictionmodi?er did not show a substantial difference in performance over the 25-100 ppmtreat levels used. However for the Tolad 9103 friction modi?er the treat level ispreferably below 50 ppm, for example about 25 ppm, in order to maintain inlet valvedeposits below a target maximum of 25 mg/valve.Example 3The additive concentrate examples according to the invention were tested forfuel economy bene?t. These concentrates were Example 1.02 (25 ppm Tolad 9103 +PIBA detergent) and Example 1.19 (50 ppm n-BAO + PIBA detergent). The resultswere compared with those of a fuel containing the same PIBA detergent but no frictionmodi?er.?CAWO 98/1117502265439 1999-03-09.13.PCT/EP97/0501 5Two tests were used: (1) A bench engine test method employing standardECE/EUDC driving cycles according to standard test PL-054, and (2) a ?eet test method .employing standard ECE/EUDC driving cycles according to standard test EG-RL80/ 1268/EWG (including amendment EG-RL 93/ 116/EWG.The results are given in Table 3 below.TABLE 3_Test Procedure Vehicles Fuel Economy Bene?t (%)25 ppm Tolad 9103 50 ppm n~BAOBench Engine Ford Sigma 1.1 0.53(3000 miles)Mercedes M1 11E 0.49 0.33Mean 0.80 0.438 Car Fleet Ford Escort 1.15 0.72Mercedes 200E 0.28 1.02Peugeot 405 1.44 2.28Rover 216 -0.22 1.30Mean 0.66 1.32The results show that a gasoline containing one of the above friction modi?ersgive an overall mean bene?t in fuel economy relative to the same gasoline without thefriction modi?er of between 0.6 and 1%, with a maximum bene?t of 1.44% for the Tolad9103 and 2.28% for the nâBao.

Claims

CLAIMS:

1. An additive concentrate comprising by weight based on the total weight of the concentrate:
(a) 0.2 to 10% ashless friction modifier which is a liquid at room temperature and pressure selected from (i) n-butylamine oleate or derivatives thereof, (ii) a substance comprising tall oil fatty acids or derivatives therof, and (iii) a mixture of (i) and (ii);
(b) 10 to 80% deposit inhibitor; and (c) 10 to 80% carrier fluid.

2. An additive concentrate according to claim 1 wherein the friction modifier (a) is n-butylamine oleate.

3. An additive concentrate according to claim 1 wherein the friction modifier (a) is a substance comprising tall oil fatty acids.

4. An additive concentrate according to claim 3 wherein the friction modifier (a) is the substance marketed under the trade name Tolad 9103.

5. An additive concentrate according to any preceding claim which does not contain any additional component incorporated as a solubilising agent for the friction modifier (a).

6. An additive concentrate according to any preceding claim wherein the amount of the friction modifier (a) is from 0.5 to 10 wt%, preferably from 1 to 4 wt%
based on the total weight of the concentrate.

7. An additive concentrate according to any preceding claim wherein the deposit inhibitor (b) is selected from polyalkylene amines, polyalkylene succinimides and a mixture thereof.

8. An additive concentrate according to any preceding claim wherein the amount of deposit inhibitor (b) is from 20 to 75 wt%, preferably from 30 to 60 wt% based on the total weight of the concentrate.

9. A fuel composition comprising combustible fuel and from 500 to 2500 ppm by weight based on the weight of the fuel of an additive combination comprising components (a), (b) and (c) as defined in any of the preceding claims.